I was running Prevx with MSE and it ran fine for a while - but then, I started to notice that sometims, the menu / general GUI of Win 7 would slow right down - eg, a click would not get a window to close. i did not have MSE and Prevx set to ignore eachothers main exe - perhaps that was the problem. Im just running Prevx at the moment - with Defender disabled as well. Runs so fast!